What does mobility even mean?

Am I the only one sick of picking a champion known for their mobility, only to be dissapointed when the enemy team has champions that ALL have some sort of leap, jump, skip, hop, cartwheel, back flip, plus a load of other annoying CC? I picked a mobile champ so I could get away from a lost fight, not to be chased down for 2 minutes by the entire enemy team. Just seems like Riot is throwing mobile abilities to any champion that has legs.